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1Author    V. A. Khokhlov, A. O. Kodintseva, E. S. FilatovRequires cookie*
 Title    "Anomalous" Thermal Conductivity of Crystalline Alkali Halides Close to Their Melting Point  
 Abstract    The thermal conductivity of crystalline alkali halides MX (M = Li, Na, K, Rb, and Cs; X = C1, Br, and I) close to their melting point has been measured by the steady-state coaxial-cylinders method. It was found to change anomalously as the temperature varied. A minimum of the thermal conduc-tivity at a characteristic temperature depends on the ionic composition of the crystal. This effect is ascribed to the formation of cooperating defects in the melting lattice. An expression relating the thermal conductivity of the ionic crystal near the melting point to the concentration of these defects is proposed. 
  Reference    Z. Naturforsch. 48a, 595—598 (1993); received April 25 1992 
  Published    1993 
  Keywords    Thermal conductivity, High temperature, Melting point, Ionic crystal, Alkali halide 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0595.pdf 
 Identifier    ZNA-1993-48a-0595 
 Volume    48 
2Author    Hk Müller-Buschbaum, H. PauschRequires cookie*
 Title    Über eine neue Präparationstechnik in der Feststoffchemie, I Hochtemperatursynthesen mit C02-Laser A New Preparation Technique in Solid State Chemistry, I High Temperature Reactions with CCVLaser  
 Abstract    A new high temperature method using a CC>2-Laser radiation is reported. Its application on solid state reactions in air or in defined gas atmospheres is described. 
  Reference    Z. Naturforsch. 34b, 371—374 (1979); eingegangen am 20. November 1978 
  Published    1979 
  Keywords    Solid State Chemistry, CC>2-Laser Preparation Method, High Temperature 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0371.pdf 
 Identifier    ZNB-1979-34b-0371 
 Volume    34 
3Author    Hk Müller-Buschbaum, H. PauschRequires cookie*
 Title    Über eine neue Präparationstechnik in der Feststoffchemie, II Hochdruck-Hochtemperatursynthesen mit C02 -Laser A New Preparative Technique in Solid State Chemistry, II High Pressure -High Temperature Reactions with CCVLasers  
 Abstract    A new technique to realize solid state reactions under high oxygen pressure is reported. This method is based on the use of CC>2-Laser radiation in combination with autoclave technique. The experimental set-up is described. 
  Reference    Z. Naturforsch. 34b, 375—377 (1979); eingegangen am 20. November 1978 
  Published    1979 
  Keywords    Solid State Chemistry, CC>2-Laser, High Pressure, High Temperature 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0375.pdf 
 Identifier    ZNB-1979-34b-0375 
 Volume    34 
4Author    Toshiyuki Takamuku, Mikito Ihara, Toshio Yamaguchi, Hisanobu WakitaRequires cookie*
 Title    Raman Spectroscopic and X-ray Diffraction Studies on Concentrated Aqueous Zinc (II) Bromide Solution at High Temperatures  
 Abstract    Raman and X-ray scattering experiments have been performed on an aqueous zinc (II) bromide solution with molar ratio [H20]/[ZnBr2] = 10 at 25 to 140 °C. The intensity of the totally symmetric Zn-Br stretching vibration (v^ for the dibromozinc(II) complex increased with increasing temper-ature while that for the tetrabromo complex decreased. A broad band assigned to the symmetric Zn-O stretching vibration (vj for the aqua zinc (I I) ion decreased in intensity with increasing temperature. The X-ray diffraction data revealed that the average number of the Zn-Br interactions within the zinc (II) bromo complexes does not change with temperature, whereas the number of Br • • • Br nonbonding interactions within the complexes decreases from 1.8 at 25 °C to 1.5 at 100 °C. From both Raman and X-ray data it is concluded that with increasing temperature the dibromo species is favored, whereas the tetrabromo and aqua zinc(II) species are unstable in the solution. The analysis of the X-ray diffraction data has shown that the mean Zn-Br bond length within the zinc (II) bromo complexes shortens gradually with increasing temperature, accompanied with an increase in the interligand Br • • • Br distance. This finding suggests that the Br-Zn-Br bond angle increases with decreasing Zn-Br distance for the lower zinc(II) bromo complexes. The equilibrium shift of the zinc (II) bromo complexes with temperature is discussed on the basis of ion-ion, ion-water, and water-water interactions. 
  Reference    Z. Naturforsch. 47a, 485—492 (1992); received November 27 1991 
  Published    1992 
  Keywords    Raman spectroscopy, X-ray diffraction, Zinc(II)bromide, High temperature, Solution structure 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0485.pdf 
 Identifier    ZNA-1992-47a-0485 
 Volume    47 
5Author    Juliane Peters, M. Soledad, Jim Énez, Domingo MoralesRequires cookie*
 Title    Effect of Extreme Temperature on Quantum Yield of Fluorescence and Membrane Leakage of the Canarian Endemic Pine (Pinus canariensis)  
 Abstract    The effect of extreme temperature on the quantum yield of fluorescence and membrane leakage of Pinus canariensis growing in 5 stands at different altitudes and orientation in Tenerife (Canary Islands, Spain) was determined. Needles were collected from the field and transferred to the laboratory where they were kept in a closed chamber with water-saturated air overnight. Then they were exposed for 30 minutes in plastic bags in a water bath at temperature treatments with steps of 2K between 56 °C and -2 4 °C and the effect was deter­ mined immediately and 24 hours after the treatment by chlorophyll fluorescence and electro­ lyte leakage. Needles presented incipient damage at temperatures ranging from -5 to -1 0 °C depending on the altitude and orientation of the stand. The results were more evident when the mea­ surements were done 24 hours after the cold treatment and values were consistent with the electrolyte leakage results. Different resistance to high temperature depending on the alti­ tude and orientation was also found, varying the temperature for incipient damage from 42 to 44 °C detected with the fluorescence parameters but not with the leakage of electrolytes which was not found until 50 °C. The amplitude of thermal limits for photosynthetic effi­ ciency alteration in needles of P. canariensis was relatively narrow and similar to that of evergreen Canarian laurel forest trees. 
  Reference    Z. Naturforsch. 54c, 681—6 (1999); received December 10 1998/February 20 1999 
  Published    1999 
  Keywords    Pinus canariensis, Low Temperature, High Temperature, Altitudinal Gradient, Chlorophyll Fluorescence, Electrolyte Leakage 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0681.pdf 
 Identifier    ZNC-1999-54c-0681 
 Volume    54